The instant invention relates to an adjustable overload clutch with automatic disengagement when a predetermined torque is exceeded. Such a clutch is especially suited for use with power-driven hand tools for pressing, cutting, etc.
A clutch in the form of a friction clutch having two clutch halves is known from DE-PS 27 09 946. In this prior art clutch, one of the clutch halves can be displaced in relation to the other half against a spring force and can be coupled to the other half. The clutch is provided with a limit load safety mechanism which makes an axial displacement of the clutch halves in relation to each other possible when activated upon reaching the limit load.
Clutches of the above-mentioned type are subjected to influences originating in the power drive, and also originating in the driven tools. These influences can negatively affect the precision with which the clutch is disengaged. These negative influences include brief torque variations acting upon the clutch from the drive side and especially from the driven side, as well as axial forces acting upon the clutch. These influences which could also be called vibrations have as a consequence that the disengagement of the clutches can occur within an undesirably wide range of errors. This leads on the one hand to an overly frequent disengagement of the clutch and therefore to its excessive wear, and on the other hand to a greater time consumption in the operation of the tool.
It is the objective of the instant invention to provide a clutch which is of simple design, can be manufactured economically, has a long life and always disengages reliably when the predetermined torque or the predetermined limit load is reached.